Field of the Invention
The invention relates to a process for recombining and/or igniting hydrogen contained in an H.sub.2 -air-steam mixture and to a device for recombining and/or igniting the hydrogen contained in an H.sub.2 -air-steam mixture.
Such a process as well as such a device are disclosed in Published European Application No. 0 303 144 A1. In that case, a catalyst body is disposed in a vertically extending tube at a distance from an inner wall of the tube. End surfaces of the tube are provided with closures which open as a function of pressure and/or temperature. The catalyst material being used is preferably palladium or platinum, and a recombination takes place even in the range of unignitable hydrogen concentrations. Attached to the catalyst body are wires which have a catalytic coating or include such a material and which, as viewed in the flow direction of the H.sub.2 -air-steam mixture through the tube, may be disposed upstream and/or downstream of the catalyst body.
The invention proceeds from the insight that the process mentioned at the outset must not only function reliably during the recombination of unignitable hydrogen concentrations and effect a reliable ignition at the so-called lower ignition limit, but that a reliable ignition of the hydrogen in the incoming mixture must also be guaranteed at the upper ignition limit (a so-called rich mixture or H.sub.2 -air-steam mixture having a relatively high H.sub.2 concentration).
This is important because, after the onset of cooling processes and condensation of the water vapor, inflow into the ignition region may take place at high H.sub.2 concentrations.